The invention relates to conveyors for the sorting of mixed cargo, especially of packages, small packets, containers and pieces of luggage, and more particularly to a conveyor having trays that tilt for the discharging of items off of the conveyor.
A prior tilting conveyor is disclosed in German Patent Specification DE 44 47 396 C1, which is incorporated herein by reference. This conveyor essentially consists of a multitude of carts, which are connected to each other and which can be moved on running rails, that form an endless transport track. The carts are chiefly constructed out of an undercarriage and a carrying tray mounted over this on support elements; the carrying tray can be swiveled from a horizontal transport position into a tilted position towards each of the two sides around a tilting axle, which runs in the direction of motion and essentially horizontally, for the delivery of the mixed cargo. Target stations, into which the mixed cargo is sorted on a preset basis through a tilting movement of the carrying tray after previously being supplied to the carrying trays through delivery stations, are arranged along the conveyor for the sorting of the mixed cargo. This sorting conveyor distinguishes itself by a simple and quickly-switching tilting device for the carrying tray.
This tilting device essentially consists of a sliding element that is guided at and between the support elements, crosswise to the direction of movement and capable mainly of movement horizontally. The sliding element moves either horizontally to the right or to the left to initiate the tilting of the carrying tray. The movement of the sliding element is initiated by rollers that are arranged on the lateral ends of the sliding element and that selectively engage curved rails positioned along the running rails. The movement of the sliding element is translated into a tilting movement of the carrying tray by a coupling lever connected on one side of the sliding element to a second lever attached to the tilting tray. This lever is connected at its center to the tilting axle running in the direction of motion, which is held at its ends by two support elements.
Two switching devices act on the sliding element at the end opposite to the lever; the switching devices are each mounted in the form of a lever around a switch shaft running horizontally and crosswise to the direction of motion. A carrier in the form of the roller that selectively engages the curved rail is mounted at the free end of the switch shaft. Each switching device can be swung around the switch shaft from a neutral position into an operating position. The switching device has a locking cam extending downwardly, viewed against the direction of motion, that latches the sliding element against the undercarriage in the neutral position, so that the carrying tray is held in the transport position.
The carrier or roller can be run into a curved rail that is C-shaped and open at the bottom to initiate and carry out the tilting movement of the carrying tray. The curved rail follows a course along the running rail in the area of the target stations. Because the curved rails each have a path that has a slight outward bend, the sliding element is pulled laterally outwards through the carrier that is guided in the curved rails. The lateral movement of the sliding element causes the coupling lever and the second lever to tilt the carrying tray to the side that lies opposite to the curved rail. Switchpoint elements designed as rollers, for example, that can be inserted from the side into the path of movement of the switching device are provided so that the switching device with its carrier can go into the curved rail starting in the area of the target station. The switching device is raised from its neutral position into an operating position that is essentially horizontal by the switchpoint elements when part of the mixed cargo is to be tipped over, so that the roller that is rotatable in this position around an axle that is essentially vertical can go into the C-shaped curved rail. The carrier is held in a vertical direction through the undercutting of the C-shaped curved rail. This conveyor for the sorting of mixed cargo has proven itself in actual use.
Another conveyor for the sorting of mixed cargo is described in the publication DE 40 90 308 T1 that likewise consists of a multitude of carts with undercarriages arranged one after the other. Each cart has a carrying tray which is arranged on top of the undercarriage and which can be laterally swiveled over a tilting axle running in the direction of motion. The driving of the carrying tray for the tilting movement, by moving carriers into curved rails following a course along the running rail, also takes place here. The conveyor distinguishes itself from the one previously described through the special design of the tilting mechanics, which essentially consist of two lateral levers coupled on the outside and beneath the carrying tray. The levers are each guided at half length through a pin in a linking guide, and the carrier for the interaction with the curved rail is mounted at the linking guide's free end. The carrier is designed as a roller that can be rotated around an axle running crosswise to the conveyor direction and essentially horizontally. It is possible to lock the carrying tray into the transport position and the tilted position with the help of the linking guide of the lever. To initiate the tilting movement, the lever has to therefore first be laterally swiveled towards the outside through the carrier, in order to unlatch the carrying tray. The roller is subsequently moved downwards by the curved rail; the carrying tray is tipped over because of this to the same side that the curved rail is placed. At the end of the tilting process, the lever is swiveled back again through the roller towards the inside, into a position that is as far vertical as possible, so that the carrying tray is locked into the tilted position.
These tilting mechanics of the conveyor for the sorting of mixed cargo have proven to be a disadvantage, because the lever has to be swiveled towards the outside and the inside for the latching and unlatching movement, and stress is consequently put on the rollers in the curved rails crosswise to their direction of motion. Wear and tear on them is consequently increased. In addition, the lever is located outside of its vertical position during the tilting movement of the carrying tray, so the axis of rotation of the roller runs at a slanted angle to its running surface. The roller only runs on one edge of its running surface during the tilting movement of the support roller because of this. Its wear and tear is also accelerated by this. Furthermore, the overall width of the individual carts is substantially increased because of the levers and the linking guides that are on the side and the outside. Additionally, the overall height of the conveyor is increased because of the arrangement of the curved rails beneath the cars, as well as their excursion to the top and bottom for carrying out the tilting movement. Further, assembly of the switchpoint elements and the curved rails that is very precise with regard to position is necessary, because positional imprecision of the switchpoint elements and of the curved rails is increased through the point of action of the levers on the carrying tray being far on the outside.
The desirability of a conveyor with a simple construction for the sorting of mixed cargo, especially of packages, small packets, containers and pieces of luggage with a compact size, which simultaneously has an optimized flow of power in the tilting mechanics can therefore be seen.